This invention relates to an angularly grooved fill sheet particularly one having horizontally extending corrugations, spaced, vertically oriented sheets of fill material whose surface is enhanced by molded-in angular zigzag grooves. Typical zig zag fill units have been known from the prior art. U.S. Pat. No. 3,540,702 shows a type of ribbed or zigzag-shaped corrugations on a slightly bent fill sheet. U.S. Pat. No. 3,733,063 shows basic zigzag-ribbed fill units having the zigzag ribs on a basically flat vertical fill sheet. U.S. Pat. No. 2,793,017 shows perpendicular intercepting corrugations in a basic fill design. None of these prior art patents show applicant's particular type of fill herein claimed.